1. Field of the Invention
The present invention relates to an auto focus apparatus and more particularly, to an auto focus apparatus which brings into focus ordinary areas as well as wide angle or close up subjects.
2. Description of the Related Art
There are two main auto focus systems in auto focus apparatus used in photographic cameras and video cameras. One is an active system such as an infrared system or an ultrasonic system, and the other is a passive system such as a Through the Camera Lens (TCL) or picture detection system.
An active auto focus system emits radio waves or sonic waves from a camera and uses waves reflected from a subject to detect the distance between the camera and the subject. On the other hand, a passive auto focus system uses information about the imaged picture from a sensor such as a charge coupled device (CCD) to control focus. In both systems, whether the camera is in focus or not is detected by using different focus information. If the camera is not in focus, a focus ring associated with a focus lens of the camera is rotated by a focus control motor to provide a proper focus. In the case where there is no focusing point, the focus ring is stopped at a predetermined position to prevent the control motor from rotating continuously. However, the picture taken will be out of focus.